This invention relates generally to so-called quick connect couplings for rapidly connecting a pair of fluid-carrying conduits in a releasably yet substantially leak-free manner. More particularly, this invention relates to an improved quick connect coupling particularly of the type disclosed and claimed in commonly assigned copending application Ser. No. 414,786, filed Sept. 3, 1982, for connection and disconnection of conduits such as ordinary garden hose or the like.
Quick connect couplings in general are known for releasably connecting a pair of fluid-carrying conduits or pipes in end-to-end relation, thereby providing a single elongated fluid flow path while permitting rapid conduit separation when desired. Such couplings typically comprise a pair of slidably interfitting male and female members adapted for respective connection to adjacent ends of the pair of conduits and further associated with a releasable locking mechanism for retaining the male and female members in locked relation. Such quick connect couplings are commonly used for releasably connecting ordinary garden hose or the like wherein the coupling is required to withstand relatively low fluid pressures without leakage. In this type of environment, it is highly desirable to provide a coupling constructed from a minimum number of components formed inexpensively, for example, from molded plastic or the like, with a geometry permitting connection or disconnection with minimum difficulty and/or manipulation of parts. At the same time, however, the coupling must be sufficiently strong to withstand axial forces and twisting forces encountered during use without breakage or undesired separation.
A variety of quick connect coupling designs have been proposed in an effort to meet the above-described design criteria. For example, according to one common coupling design, interfitting male and female members are associated with a twist lock mechanism wherein the coupling is connected by inserting the male member into the female member and then twisting the members relative to each other to seat internal locking tabs within corresponding locking recesses. With this type of coupling, however, the requisite twisting movement imparts a corresponding twist to the hoses which typically have a resilient plastic or rubber construction tending to return to an untwisted state, thereby occasionally unlocking the coupling.
Alternative quick connect couplings for garden hoses and the like have been proposed wherein the male and female members are locked and unlocked without significant twisting movement, such as those devices depicted in U.S. Pat. Nos. 3,990,727 and 4,216,982. Devices of this type, however, have generally included relative complex locking mechanisms having a relatively large number of mechanical parts thereby increasing the cost of the coupling and the likelihood of mechanical failure. Alternatively, these devices have included locking mechanisms which are particularly difficult to align for proper connecting and disconnecting movement or which include relatively small and typically beveled locking surfaces which are unable to withstand significant axial loads during use without separation or breakage.
In copending application Ser. No. 414,786, an improved quick connect coupling is disclosed wherein a relatively simple, C-shaped locking retainer is provided for releasable connection of male and female members without twisting movement. The C-shaped retainer is carried about the female member and includes locking arms extending through arcuate slots in the female member for normal locked reception into an aligned circumferential groove in the male member to lock the coupling. In this normal position, free ends of the locking arms ride against radially oriented cam surfaces on the female member, whereby the locking arms can be forced against the cam surfaces resulting in increased radial separation of the arms sufficient to disconnect the male and female members. While this quick connect coupling provides significant improvements with respect to previous coupling designs, occasional inadvertent disconnection can still occur, particularly when the coupling is subjected to water pressure simultaneusly with substantial twisting forces derived, for example, from a twisted hose to which the coupling is connected.
The present invention overcomes the problems and disadvantages of the art by providing a further improved quick connect coupling of the general type described and claimed in copending application Ser. No. 414,786, where the coupling further includes means for positively locking the coupling against the inadvertent separation when the coupling is subjected to water pressure.